Telematics services are those services that are provided by a call center to a vehicle and/or to the operator of a vehicle via an automatic and/or on-demand communications link connecting the call center to the vehicle. Some of the more common telematics services include, but are not limited to, turn-by-turn navigation guidance, assistance during times of emergency, cellular telephone services, door unlock services, and the remote monitoring of a vehicle's maintenance requirements.
A vehicle that is capable of providing its driver with such telematics services historically has included an embedded telematics unit that is mounted to the vehicle and that is configured to communicate with both the call center and the vehicle bus. The communicative connection between the embedded telematics unit and the call center is a wireless connection and the communicative connection between the embedded telematics unit and the vehicle bus is a wired connection.
The wired connection between the embedded telematics unit and the vehicle bus enables the telematics unit to communicate and interact with any vehicle module that is also connected to the vehicle bus. As a result of this wired connection between the embedded telematics unit and the vehicle bus, the call center may also communicate and interact with any vehicle module connected to the vehicle bus. This link makes it possible to provide the driver with many of the telematics services that are offered.
Because of the popularity of telematics services, aftermarket telematics units are beginning to enter the market place. Such aftermarket telematics units make it possible for drivers of vehicles that lack an embedded telematics unit to, nevertheless, receive some or all of the available telematics services. The aftermarket telematics unit may be mounted to the vehicle and may be wired into to the vehicle's electrical system or battery to draw the power that is needed to operate the aftermarket telematics unit.
Forming a wired connection between the aftermarket telematics unit and the vehicle bus, however, has proved challenging and in many instances, impractical. One alternative has been to establish a wireless connection between the aftermarket telematics unit and the vehicle bus using a vehicle communication interface device (“VCI device”), also known as a dongle. The VCI device is configured to connect to a vehicle's assembly line diagnostic link (ALDL) which provides direct access to the vehicle bus. The VCI device is also configured to communicate wirelessly with the aftermarket telematics unit. This configuration allows the VCI device to serve as an interface between the aftermarket telematics unit and the vehicle bus.
One consideration when deploying this solution is that the ALDL is configured to provide a continuous source of power to the VCI device. This power will be supplied even when the vehicle is turned off. Therefore, it is desirable to turn the VCI device off during periods when the vehicle is turned off to avoid depleting the vehicle's battery. However, a countervailing consideration is that the call center may need to communicate with one or more vehicle components over the vehicle bus even during periods when the vehicle is turned off. Therefore, it is desirable to keep the VCI device turned on during periods when the vehicle is turned off to provide the call center with continuous access to the vehicle bus.